Empirical Validation of the Bio-Cycle Fixation Model
Classical population genetics models systematically overpredict the rate of evolutionary change in species with overlapping generations. The math is straightforward: when grandparents, parents, and children coexist and compete for the same resources, not every “generation” represents a fresh opportunity for selection to act. The human population doesn’t reset with each breeding cycle, instead, people gradually age out of it as new children are born.
The Bio-Cycle Fixation Model isn’t a refutation of classical population genetics, but an extension. Kimura’s model assumes discrete generations (d = 1.0). The Bio-Cycle model adds a parameter for generation overlap (d < 1.0). When d = 1.0, the models are identical. The question is empirical: what value of d fits real organisms?
In this appendix, we present four tests. The first demonstrates why generation overlap matters by comparing predictions for organisms with different life histories. The remaining three validate the model against ancient DNA time series from humans, where we have direct observations of allele frequencies changing over thousands of years.....
What This Means
The Bio-Cycle Fixation Model extends Kimura’s framework to account for overlapping generations. For humans, the empirically validated correction is d = 0.45—meaning effective generations are 45 percent of nominal generations.
When we calculate the number of substitutions possible over evolutionary time, it is necessary to use effective generations rather than nominal ones. With d = 0.45 and 450,000 nominal generations since the human-chimp split 9 million years ago, we have approximately 202,500 effective generations for selection to act.
This isn’t theoretical speculation. Three independent ancient DNA time series converge on the same value. That’s not an accident. It’s a reflection of the real world.